[DO NOT MERGE] [pdata] Consolidate CopyOrig logic for slices

[dmitryax]

Use the same copy logic for primitive slices as for the complex.

The opposite approach of #13293.

Apparently, there is slight improvement when 10-items slice is copied into 7-items slice.

Not sure if we want to complicate the logic for this insignificant gain.

before

goos: darwin
goarch: arm64
pkg: go.opentelemetry.io/collector/pdata/internal
cpu: Apple M1 Max
BenchmarkCopyOrigInt64Slice/0_to_7-10         	 8608524	       139.9 ns/op	       0 B/op	       0 allocs/op
BenchmarkCopyOrigInt64Slice/1_to_7-10         	 8533219	       140.2 ns/op	       0 B/op	       0 allocs/op
BenchmarkCopyOrigInt64Slice/7_to_7-10         	 8768828	       137.3 ns/op	       0 B/op	       0 allocs/op
BenchmarkCopyOrigInt64Slice/10_to_7-10        	 7211601	       164.7 ns/op	     112 B/op	       1 allocs/op
BenchmarkCopyOrigInt64Slice/20_to_7-10        	 7005366	       171.8 ns/op	     160 B/op	       1 allocs/op
BenchmarkCopyOrigInt64Slice/50_to_7-10        	 5943145	       209.0 ns/op	     416 B/op	       1 allocs/op

after

BenchmarkCopyOrigInt64Slice/0_to_7-10         	 8667313	       140.1 ns/op	       0 B/op	       0 allocs/op
BenchmarkCopyOrigInt64Slice/1_to_7-10         	 8764303	       136.8 ns/op	       0 B/op	       0 allocs/op
BenchmarkCopyOrigInt64Slice/7_to_7-10         	 8669146	       139.0 ns/op	       0 B/op	       0 allocs/op
BenchmarkCopyOrigInt64Slice/10_to_7-10        	 7425303	       160.8 ns/op	      80 B/op	       1 allocs/op
BenchmarkCopyOrigInt64Slice/20_to_7-10        	 6743520	       177.6 ns/op	     160 B/op	       1 allocs/op
BenchmarkCopyOrigInt64Slice/50_to_7-10        	 5643139	       213.9 ns/op	     416 B/op	       1 allocs/op

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.61%. Comparing base (c6cd1ae) to head (e48bf83).

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #13294   +/-   ##
=======================================
  Coverage   91.61%   91.61%           
=======================================
  Files         522      522           
  Lines       29120    29126    +6     
=======================================
+ Hits        26679    26685    +6     
  Misses       1925     1925           
  Partials      516      516           

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